I don't think any of YC fundees really need YC funding. Most of their friends and families would be able to sponsor a summer's worth of living expenses. I think YC's true value lies in the community of cofounders, connections of PG and Co and the visibility that being a YC startup generates. So, a being funded b YC would be useful to anyone who needs help in these three areas even if the have money. I have enough money to live comfortably for a year saved up but if the US immigration system was more lenient I would have applied to YC in a heartbeat.